Financial Derivatives and Hedging - Changes in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2018
AOCI Attributable To Parent, Before Reclassification And Tax [Roll Forward]
Beginning balance	$ 3,628.6	$ 3,307.8	$ 3,175.8
Amount recognized in other comprehensive income on interest rate swaps contracts, tax benefit	5.0
Amount reclassified from other comprehensive income into earnings, tax expense	0.9
Ending balance	3,824.8	3,628.6	3,307.8
Accumulated Gain (Loss), Net, Cash Flow Hedge, Before Tax, Parent
AOCI Attributable To Parent, Before Reclassification And Tax [Roll Forward]
Beginning balance	0.0
Ending balance	(17.1)	0.0
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent
AOCI Attributable To Parent, Before Reclassification And Tax [Roll Forward]
Beginning balance	0.0	0.0	0.0
Amount recognized in other comprehensive income on interest rate swap contracts (net of tax of $5.0 million)	(20.8)
Amount reclassified from other comprehensive income into earnings, gross (net of tax of $0.9 million)	3.7
Ending balance	$ (13.0)	$ 0.0	$ 0.0